Check or not, it is part of the car that needs to work and should work. You just spunked a load of money on a BMW AUC. Get on the phone
If they are not helpful just pester them until they give in, which they will.
Some garages are poor, others are really helpful. Don't go in all guns blazing but be prepared for a war lol. These things can take some grit sometimes.
Don't speak to BMW UK, speak to the garage you bought it from.